title: Viewpoints: diet and dietary adaptations in early hominins: the hard food perspective.
abstract: Recent biomechanical analyses examining the feeding adaptations of early hominins have yielded results consistent with the hypothesis that hard foods exerted a selection pressure that influenced the evolution of australopith morphology. However, this hypothesis appears inconsistent with recent reconstructions of early hominin diet based on dental microwear and stable isotopes. Thus, it is likely that either the diets of some australopiths included a high proportion of foods these taxa were poorly adapted to consume (i.e., foods that they would not have processed efficiently), or that aspects of what we thought we knew about the functional morphology of teeth must be wrong. Evaluation of these possibilities requires a recognition that analyses based on microwear, isotopes, finite element modeling, and enamel chips and cracks each test different types of hypotheses and allow different types of inferences. Microwear and isotopic analyses are best suited to reconstructing broad dietary patterns, but are limited in their ability to falsify specific hypotheses about morphological adaptation. Conversely, finite element analysis is a tool for evaluating the mechanical basis of form-function relationships, but says little about the frequency with which specific behaviors were performed or the particular types of food that were consumed. Enamel chip and crack analyses are means of both reconstructing diet and examining biomechanics. We suggest that current evidence is consistent with the hypothesis that certain derived australopith traits are adaptations for consuming hard foods, but that australopiths had generalized diets that could include high proportions of foods that were both compliant and tough.
authors.affiliation: Department of Anthropology, University at Albany, Albany, NY 12222, USA. dstrait@albany.edu
authors.forename: David S
authors.initials: DS
authors.lastname: Strait
authors.forename: Paul
authors.initials: P
authors.lastname: Constantino
authors.forename: Peter W
authors.initials: PW
authors.lastname: Lucas
authors.forename: Brian G
authors.initials: BG
authors.lastname: Richmond
authors.forename: Mark A
authors.initials: MA
authors.lastname: Spencer
authors.forename: Paul C
authors.initials: PC
authors.lastname: Dechow
authors.forename: Callum F
authors.initials: CF
authors.lastname: Ross
authors.forename: Ian R
authors.initials: IR
authors.lastname: Grosse
authors.forename: Barth W
authors.initials: BW
authors.lastname: Wright
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Wood
authors.forename: Gerhard W
authors.initials: GW
authors.lastname: Weber
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Craig
authors.initials: C
authors.lastname: Byron
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Slice
authors.forename: Janine
authors.initials: J
authors.lastname: Chalk
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Smith
authors.forename: Leslie C
authors.initials: LC
authors.lastname: Smith
authors.forename: Sarah
authors.initials: S
authors.lastname: Wood
authors.forename: Michael
authors.initials: M
authors.lastname: Berthaume
authors.forename: Stefano
authors.initials: S
authors.lastname: Benazzi
authors.forename: Christine
authors.initials: C
authors.lastname: Dzialo
authors.forename: Kelli
authors.initials: K
authors.lastname: Tamvada
authors.forename: Justin A
authors.initials: JA
authors.lastname: Ledogar
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D000883:Anthropology / Q000379:methods*; D005075:Biological Evolution; D002247:Carbon Isotopes / Q000032:analysis; D003743:Dental Enamel / Q000033:anatomy & histology; D004032:Diet; D004435:Eating; D020342:Finite Element Analysis; D015186:Hominidae / Q000033:anatomy & histology* / Q000502:physiology
chemical_list: D002247:Carbon Isotopes